The invention relates to a device, in particular a therapy device for the application of acoustic shock waves and comprising a housing with a coupling surface for coupling the shock waves into the body to be treated, a shock wave generating device, and a means suitable for focusing the shock waves.
Therapy devices of this kind for the application of acoustic shock waves are used, for example, for lithotripsy or for human applications in the field of orthopaedics. The therapy device is also used in the field of veterinary medicine.
In this context the region to be treated is located and a necessary number of acoustic shock waves are applied. In this context the region to be treated can be located at varying distances from the surface of the patient's body. This distance depends on:
1) the type of region to be treated (e.g. renal calculi or soft-tissue structures) and
2) the patient's constitution (i.e. obese or not obese).
The penetration depth of the acoustic shock waves is defined by the site of shock wave generation and the geometry of the shock wave focusing device.
For positioning the shock wave focus in the particular regions in the patient's body to be treated, which regions are located at different depths, therapy devices with different fixed or variable penetration depths are required.
It is known from DE 195 09 004 C1 that, in a device of the above-named type, exchangeable coupling attachments, e.g. coupling pads or coupling cushions, are foreseen in order to vary the distance between the shock wave generating device and the coupling surface of the shock waves in the patient's body, whereby the position of the shock wave focus can be adjusted on the region in the patient's body to be treated. It has been noted, however, that the additional coupling surface results in poorer transmission of energy by the shock waves. Furthermore, no infinitely adjustable penetration depths are possible but only predetermined penetration depths corresponding to the thickness of the coupling pad or coupling cushion. In addition, the mounting of the coupling inserts makes the handling of the device more complicated.
A device of the kind mentioned at the beginning, in which various hand-held therapy devices with different penetration depths can be connected in a detachable manner to a supply unit, is known from DE 197 18 511 C2. Here again no infinitely variable adjustment of penetration depth is possible. The therapy heads must be replaced in each case for different applications.
In DE 199 35 724 A1 a therapy device is described in which the coupling membrane provided for coupling the device to the patient has a flexible design and can be moved at various distances from the treatment site via coupling fluid displacement and can be placed on the patient's body. The distance between the shock wave generating device and the coupling surface provided for coupling the shock waves into the body of the patient to be treated is thus variable. Infinitely variable adjustment of the penetration depth of the shock waves in the patient's body is thereby achieved. However, an elastic coupling membrane is required in the above-named device; this membrane is subject to rapid aging owing to the heavy demands placed on it. Furthermore, a compressed air device with a corresponding compressed air line is necessary to control the displacement of coupling fluid. The inconvenient handling as well as the complicated and cost-intensive manufacture due to the additional compressed-air generating device, have proven to be disadvantageous.
A common feature of all of the above-mentioned variants is that either the coupling membrane is moved or additional parts are necessary. This shortens the life cycle of the device and makes handling complicated.
Against the background of the above-mentioned embodiment, the essential thought of the invention is to improve a device of the kind mentioned at the beginning such that it achieves a high flexibility of application as well as fast and simple positioning of the shock wave focus in the therapy region with only a small transmission loss by the shock waves.